MI Water Operator cheat sheet

Coagulation neutralizes particle surface charge; optimum coagulant dose and pH are determined by jar test.

Conventional treatment sequence: coagulation, flocculation, sedimentation, filtration, disinfection.

Michigan turbidity limits for conventional filtration: ≤0.3 NTU in at least 95% of monthly samples and never >1 NTU.

CT (mg/L·min) = disinfectant residual concentration × contact time; required CT varies with disinfectant, pH, temperature, and target log inactivation.

Chlorine demand = applied dose − residual after contact time; breakpoint is the dose where free residual begins to persist.

Fluoride: primary MCL 4.0 mg/L, secondary standard 2.0 mg/L, typical target dose 0.7 mg/L.

Filter backwash is triggered by terminal head loss, turbidity breakthrough, or maximum run time; backwash must fluidize media without media loss.

Slow sand filters rely on the schmutzdecke and operate at low loading rates; cleaning is by scraping the surface layer.

Corrosion control commonly involves pH and alkalinity adjustment or phosphate inhibitor addition to reduce lead and copper release.

Minimum pressure is 20 psi under all conditions; normal operating pressure is typically 40–80 psi.

A pressure drop below 20 psi requires a boil water advisory and Tier 1 public notice within 24 hours.

Total coliform MCL: for systems with <40 routine samples/month, more than one positive sample; for ≥40, more than 5% positive.

Stage 2 DBPR MCLs: TTHM 80 µg/L and HAA5 60 µg/L as locational running annual averages.

Michigan lead action level is 12 ppb at the 90th percentile; federal action level is 15 ppb.

Backflow protection hierarchy: air gap > reduced-pressure zone > double check valve > atmospheric vacuum breaker.

Main flushing targets velocities of at least 2.5 ft/s to scour sediment; hydrant flow tests measure available flow and pressure.

High water age increases DBP formation and reduces disinfectant residual; storage tank turnover and dead-end elimination reduce age.

Drawdown (ft) = static water level − pumping water level; specific capacity (gpm/ft) = pumping rate ÷ drawdown.

Well casing must extend above grade and be grouted with a sanitary seal to prevent surface contamination.

New or repaired wells are shock chlorinated, commonly at 100 mg/L, and held at least 24 hours before pumping to waste.

GWUDI systems must provide 4-log virus treatment under the Groundwater Rule.

Wellhead protection areas are delineated by time of travel, commonly a 5-year travel time.

Well development removes drilling fines and restores yield; surging, bailing, and jetting are common methods.

Pumping tests measure aquifer yield and well efficiency; step tests determine safe pumping rate.

Michigan EGLE's Drinking Water and Environmental Health Division administers the state drinking water program with EPA oversight.

Consumer Confidence Reports are due to customers by July 1 each year.

Public notice tiers: Tier 1 within 24 hours, Tier 2 within 30 days, Tier 3 within one year.

Monthly operating reports (MORs) document flows, doses, residuals, and compliance data submitted to EGLE.

Michigan's Lead and Copper Rule action level is 12 ppb; systems must complete service line inventories and replacement.

Groundwater Rule requires 4-log virus treatment or monitoring for at-risk groundwater systems.

Stage 2 DBPR compliance is based on locational running annual averages at each monitoring site.

Certified operators are required for community water supplies; renewal requires continuing education units.

Chlorine gas IDLH is 10 ppm; responders use supplied-air SCBA and evacuate upwind because gas is heavier than air.

Confined space entry requires a permit, atmospheric testing, and oxygen between 19.5% and 23.5%.

Trenches 5 ft deep or deeper require a protective system; spoil piles are kept at least 2 ft from the edge.

Lockout/tagout: isolate energy sources, apply locks and tags, and verify zero energy before work.

A four-gas meter monitors oxygen, combustible gas (LEL), hydrogen sulfide, and carbon monoxide.

Loss of pressure below 20 psi triggers a boil water advisory and Tier 1 public notice within 24 hours.

Security plans include vulnerability assessments, access control for chemicals, and key control.